Adds UMA to measure when the data reduction proxy via header is missing

chrome/browser/net/chrome_network_delegate.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/net/chrome_network_delegate.h"
 
 #include <stdlib.h>
 
 #include <vector>
 
@@ skipping 568 matching lines @@
       int64 adjusted_original_content_length =
           data_reduction_proxy::GetAdjustedOriginalContentLength(
               request_type, original_content_length,
               received_content_length);
       AccumulateContentLength(received_content_length,
                               adjusted_original_content_length,
                               request_type);
       RecordContentLengthHistograms(received_content_length,
                                     original_content_length,
                                     freshness_lifetime);
+
       if (data_reduction_proxy_enabled_ &&
           data_reduction_proxy_usage_stats_ &&
           !proxy_config_getter_.is_null()) {
+        data_reduction_proxy_usage_stats_->RecordMissingViaHeaderBytes(request);

[mmenke, 2014/09/18 18:39:30]

This function name is very confusing, since it's always called, even when we
have a via header.  Also seems weird that this takes request and the next takes
*request.

I think to keep things simplest, you should just merge them into
DataReductionProxyUsageStats::RecordByteHistograms(*request,
*data_decution_proxy_enable_, proxy_config_getter_.Run());

[sclittle, 2014/09/19 01:05:01]

Done.

+
         data_reduction_proxy_usage_stats_->RecordBypassedBytesHistograms(
             *request,
             *data_reduction_proxy_enabled_,
             proxy_config_getter_.Run());
       }
       DVLOG(2) << __FUNCTION__
           << " received content length: " << received_content_length
           << " original content length: " << original_content_length
           << " url: " << request->url();
     }
@@ skipping 231 matching lines @@
     data_reduction_proxy::DataReductionProxyRequestType request_type) {
   DCHECK_GE(received_content_length, 0);
   DCHECK_GE(original_content_length, 0);
   StoreAccumulatedContentLength(received_content_length,
                                 original_content_length,
                                 request_type,
                                 reinterpret_cast<Profile*>(profile_));
   received_content_length_ += received_content_length;
   original_content_length_ += original_content_length;
 }